[BUG] libguestlib.so is loaded twice if LD_PRELOAD it

**Describe the bug**
A clear and concise description of what the bug is.

**To Reproduce**
libguestlib.so will be loaded twice if we specify LD_PRELOAD. If we don't specify LD_PRELOAD, some program will segfault or doesn't talk to the ava manager. 

**Expected behavior**
The guestlib should only load once. 
